title: Powdery mildew resistance in tomato by impairment of SlPMR4 and SlDMR1.
abstract: Genetic dissection of disease susceptibility in Arabidopsis to powdery and downy mildew has identified multiple susceptibility (S) genes whose impairment results in disease resistance. Although several of these S-genes have been cloned and characterized in more detail it is unknown to which degree their function in disease susceptibility is conserved among different plant species. Moreover, it is unclear whether impairment of such genes has potential in disease resistance breeding due to possible fitness costs associated with impaired alleles. Here we show that the Arabidopsis PMR4 and DMR1, genes encoding a callose synthase and homoserine kinase respectively, have functional orthologs in tomato with respect to their S-gene function. Silencing of both genes using RNAi resulted in resistance to the tomato powdery mildew fungus Oidium neolycopersici. Resistance to O. neolycopersici by SlDMR1 silencing was associated with severely reduced plant growth whereas SlPMR4 silencing was not. SlPMR4 is therefore a suitable candidate gene as target for mutagenesis to obtain alleles that can be deployed in disease resistance breeding of tomato.
authors.affiliation: Laboratory of Plant Breeding, Wageningen University and Research Centre, Wageningen, The Netherlands.
authors.forename: Robin P
authors.initials: RP
authors.lastname: Huibers
authors.forename: Annelies E H M
authors.initials: AE
authors.lastname: Loonen
authors.forename: Dongli
authors.initials: D
authors.lastname: Gao
authors.forename: Guido
authors.initials: G
authors.lastname: Van den Ackerveken
authors.forename: Richard G F
authors.initials: RG
authors.lastname: Visser
authors.forename: Yuling
authors.initials: Y
authors.lastname: Bai
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001203:Ascomycota / Q000502:physiology; D001483:Base Sequence; D017124:Conserved Sequence; D060467:Disease Resistance / Q000187:drug effects / Q000235:genetics; D005964:Glucosyltransferases / Q000235:genetics* / Q000378:metabolism; D006714:Homoserine / Q000378:metabolism / Q000494:pharmacology; D018551:Solanum lycopersicum / Q000235:genetics* / Q000254:growth & development / Q000382:microbiology; D008969:Molecular Sequence Data; D009154:Mutation; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics* / Q000378:metabolism; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D034622:RNA Interference
chemical_list: D029681:Arabidopsis Proteins; D010940:Plant Proteins; D006714:Homoserine; D005964:Glucosyltransferases; C020570:1,3-beta-glucan synthase; D017853:Phosphotransferases (Alcohol Group Acceptor); C021370:homoserine kinase